THE DIAMOND PAGE — Archangel sizes up pipe in Russia

Delineation drilling at the Verkhotina diamond project in northwestern Russia continues to expand pipe 441.

The project is a 40-50 joint venture held by Vancouver-based Archangel Diamond (AAD-V) and the Russian state entity, Archangelskgeoldobycha. The remaining 10% is held privately.

Hole 46, an 80-metre stepout west of hole 48, was stopped in kimberlite at a depth of 301 metres. It had intersected the crater facies of the pipe, beginning at a 65-metre depth.

Stepping out 130 metres north of previously reported hole 43, the crater facies was intersected by hole 41 at a depth of 62 metres. It failed to hit the diatreme phase and entered into country rock at 186 metres of depth.

Archangel reports the diatreme pipe remains open to the west and measures more than 8 ha in size. The crater facies, which comprises bedded sandstones and tuffaceous breccias, is open in all but the southern direction.

Initial results from hole 48 give a preliminary grade of 159 carats per 100 tonnes (1.59 carats per tonne) for the diatreme phase and 28 carats per 100 tonnes (0.28 carat per tonne) for the crater facies. The grade estimate is based on macrodiamonds measuring greater than 1 mm in one dimension.

Hole 48 intersected the crater facies at a 70-metre depth and the diatreme at about 200 metres before stopping in kimberlite at just over 300 metres.

A 1,078.3-kg sample of the crater facies yielded 21 macros, including 7 stones measuring between 1 and 2 mm, and one stone measuring between 2 and 4 mm. The kimberlite diatreme returned 86 macros from 886.6 kg of sample. The diamonds included 24 stones measuring between 1 and 2 mm, and three stones measuring between 2 and 4 mm.

Final mineralogical inspection and cleanup of the process plant resulted in a revised count for previously reported hole 49. A 918.4-kg sample of the crater facies returned a total of 62 macros, including 17 measuring between 1 and 2 mm, and 1 measuring between 2 and 4 mm, for a preliminary grade of 73 carats per 100 tonnes (0.73 carat per tonne).

A 1,068.1-kg sample of the kimberlite diatreme yielded 157 macros, including 28 measuring between 1 and 2 mm, and 7 measuring between 2 and 4 mm. A grade is calculated at 251 carats per 100 tonnes (2.51 carats per tonne).

Based on the holes drilled to date on pipe 441, which have collected 2.7 tonnes of diatreme and 4 tonnes of crater facies, the kimberlite diatreme averages a grade of 190 carats per 100 tonnes (1.9 carats per tonne), while the crater facies grades 30 carats per 100 tonnes (0.3 carat per tonne).